PURPOSE: To investigate the impact of genicular artery embolization (GAE) on synovitis in knee osteoarthritis (OA) using contrast-enhanced magnetic resonance (MR) imaging and to assess its predictive role in pain response. MATERIALS AND METHODS: A single-center retrospective analysis was conducted using contrast-enhanced MR imaging on 33 patients treated with GAE for knee OA between December 2022 and March 2023. MR assessments before the procedure and at 3 months after embolization were utilized in a semiquantitative scoring system for synovitis severity and distribution analysis. Pain and function through Western Ontario and McMaster Universities Osteoarthritis Index and visual analog scale scores were also assessed. RESULTS: Significant synovitis reduction was noted after GAE, particularly in parapatellar and periligamentous areas. Synovial contrast enhancement scores significantly decreased from 5.1 (SD ± 2.0) to 2.9 (SD ± 2.0) at 3 months (P < .001), with a moderate negative correlation between synovial enhancement scores and pain levels (P = .005). CONCLUSIONS: GAE significantly reduced synovitis in knee OA, evidenced by contrast-enhanced MR imaging. The correlation between preprocedural synovial contrast enhancement scores and pain relief after the procedure, although promising, requires careful interpretation because of the complex factors affecting pain in knee OA.